Non running MGB puts up a real fight

A ‘74 MGB that the new owner can’t get to start after sitting for a few years comes into the shop for me to get running. Based on the story of the car, this should be a fairly straightforward and easy job for me…
The car on the other hand, had other plans. It simply wasn’t ready to easily be coaxed back into action and it made for a much longer day than expected.

[@michaelstoliker971]

I know nothing about these carburetors...so lets rip them out and put in an equally finicky Italian carb that was used in Pintos, Mustang II's, and several types of Fiats. These carbs are very reliable if set up properly by someone that knows them, but if they've sat for years and are very varnished it can take nuclear weapons to clean up the float bowls.

[@mgbgtguy]

That’s how most webers end up on MG’s. Some even believe they are “performance Carburetors” 😂 …not on that crappy intake they sell for them they aren’t. I will take SU’s ANY day over a Weber

[@aggiebq86]

I don’t think I’ve seen a set of SUs so finicky. Usually once you’ve cleaned any varnish out, replaced o rings and set the clearances up, they will fire right up. Very neat paint job.

[@mitchd949]

If it was me, once I saw the first sign that the carbs were assembled incorrectly (front and rear jets swapped), I would have stopped right there and torn both carbs apart completely and reassembled. Either the prior owner was the hack or he paid some hack garage owner for bad work.

[@americanpatriot2422]

Always an outstanding video and presentation. I never liked the HIF carbs. I prefer the The earlier models.

[@mgbgtguy]

The biggest issue with the HIF series carb is access to the float bowls (easier on the early ones) but on the plus side, those integrated float bowls, have less fuel starvation issues in hard cornering than the early ones. I guess that’s a trade-off in someways. Usually I have no problem tuning them and don’t personally have any dislike for them.

[@MichaelmhAshley]

Great! Thanks for your efforts in making such an appropriate video. Better than tech support. Thanks. Mike

[@roberthartmaier6643]

They have the turn indicators on backwards. The higher pointy part should be on the inside next to the grill.

[@mgbgtguy]

I see them both ways all the time, I hardly pay attention anymore when it’s a car I’m working on for someone else

[@mundanestuff]

So the carbs being out of adjustment for choke, out of adjustment because the needles were backwards, etc, were soaking the rear spark plugs causing them to misfire? The fact that electricity was getting to the plug was proved by the timing light test?

[@mgbgtguy]

Once that carb was getting fuel, if was feeding too much in and yes soaked plugs will misfire ( that’s what’s usually referred to as fouled plugs). Yes the timing light confirms a spark is being sent to the plug (spark tester does the same thing, but this is easier/ faster)

[@MGB-learning]

Great video

[@mgbgtguy]

Thanks, that car was a pain

[@pw601]

Assumptions about what people have done to a poorly running vehicle are a rabbit hole. Even if they haven't been touched the o rings in the carbs are potentially 40 years old and throttle bushes worn with air leaks. If they have been interfered with its better to assume nothing is correct and do a thorough disassembly, clean and rebuild referring to a works diagram. SU's are a deceptively simple carb, capable of accurately metering the fuel demands of the engine. Needle swaps may get you into the right ball park, but reproducing the needle at specific points may be necessary.

[@pw601]

Reprofiling!

[@RickCoMatic]

It breaks my heart watching someone not as familiar with matters related to getting a severely hacked later MGB: a) Running! When you see those AIR RAIL Ports Plugged ... and that ... emissions 'stuff' missing from the Mount that morphed out from the Thermostat Housing, NO Piston Crowns, Pistons w/ concave Compression Lowering mods, Carbs which ARE NOT S.U.'s w/ External Floats, and evidence inexperienced hands have blazed the trail to oblivion you're following; STOP! There is NO satisfaction to be had spending TIME attempting to make that baby run good without mods. Look for a NO Smog Cylinder Head. Performance Intake Manifold & Carb Kit. (WEBER™) 4 Into 1. Header New Set of Pistons & Rings Performance Electronic Ignition Complete Camshaft Modified -- Isky Cams T-32. (pull Cam ship to Isky - Gardina CA Oil Cooler Reliable Fuel Pump Rear Deck Lid / Repair -- Straighten - Add Gusset - Pimp. Exchanging Pistons for Performance Pistons may be done w/ Engine in situ.

[@mgbgtguy]

I play with the late mgb’s all the time. This one ran perfectly fine on a different set of carburetors that I had laying on the floor, it just didn’t want to run on on the carbs that were on it. It had been a while since I’ve really done much real diagnosis and I was in the wrong mindset and admittedly, struggling a little bit with this one. Modifying an emissions motor isn’t the only way to make it run good, I know…I’ve made many of them run perfectly well over the years. it just won’t have as much power, and the owner just wanted it to run, he didn’t care about the extra power and spending all that money. I don’t know why there’s so much hate on the integrated float SU,s …so many people think the only ones worth using are the ones with the side float bowls. I’ve worked with many sets of HIF carbs and I’ve run them on my car with various performance modifications for many years. I can’t believe you actually think the Weber carb is the way to go, especially if you’re talking the DGV. There’s nothing performance about those as the provided manifold is not very good.

[@BobHerman-v9o]

If you had to over-richen the carbs you might want to check for wear in the carb bodies where the butterfly shafts seat. That would make them run lean, especially at idle.

[@mgbgtguy]

That was checked, this car had HIF-4 carbs on it. They have shaft seals and are not nearly as prone to that wear as the earlier carbs.

[@philmurphy3549]

Thanks for the video, the whole process of finding out the issue was very useful thanks 👍

[@davidwitham5588]

Instead of taking the valve cover off you can put your fingers through the oil filler and feel what the rockers are doing. At your own risk!

[@anthonyhfe6450]

So the root cause of the rear two cylinders not firing and just getting wet with fuel was a choke device was out 180 degrees on the rear carb? And another issue is someone mixed up the two jets, right ?Interesting. 🤔. Glad I didn't mix mine up. You really gotta be careful and focus on each step. Thnx for the video ! Helpful.

[@bladerunner6282]

i guess i've been shocked once too often to feel confident pulling plug wires off sparkplugs on an engine that's running. i wish i could. in fact, i'm reluctant to even touch the cap. .... so maybe it's time to invest in a cheap pair of rubber gloves or something, eh?

[@tedmoss]

I learned how to take apart those SU carbs in 1955 when I was 12 years old, watching my father work on his MG TD.

[@TC-qd1zw]

SUs hate to fiddled with.

[@mgbgtguy]

I don’t mind filling with them, usually I get them working with very little fuss, but this particular set did give me troubles

[@bluzzjazz]

I have a 74 1/2 which has run fine for the past 10 years. Sits up over the winter here in NC and sometimes I'll need to charge the battery. This time, my motorcycle got most of my attention and the battery was stone dead

[@mgbgtguy]

That’s a good place to start, make sure you’re getting fuel to the carbs

[@Lstimey]

Any ideas how to eliminate the burble in the exhaust while shifting gears at hard acceleration. 74 with Hif's

[@mgbgtguy]

Well.. that depends on what you mean by burble. I would need something a bit more specific/descriptive

[@michaelstoliker971]

Thanks for not going the Weber route.

[@mgbgtguy]

I don’t like the Weber, I’d rather see a Stromberg on a car than one of those 😜